Typewriter



Nov. 22, 1927.

J. C. REDDICK -TYPEWRITER Filed May 26, 1924 NVZ/VTOR 30 J. C. RZDD/CKHTTORNEYS Patented Nov. 22, 1927.

UNITED; STATES JOHN GOATSWOBTH nnnniok, or TORONTO,1ONTARIO; CANADA.

intention relates to'improvements in typewriters, and the object, of theinvention" is "to devise means for eliminating theobjection able chokingor clo'gging efi'ec t producedby the substitution of'a resilient platefor. the usual hard metal or anvil ring, and to obviate the extremeaccuracy necessary for' producing the resilient plate hithertoconstructed and thereby simplifying and cheap'ening' the tnianufac'ture,and at the I I I opposite edge, or the edge remote from .the

same time providing'a resilient stop which improves the keyboard touch,increases the speed, eliminates/noise, and produces very sharp andclearprintingan'd also under op- I r eration preserves the alignment byreducing the wear upon the parts,"and it consists essentially of a 1'esilient'plate mounted upon a type bar segment or othersupporting memberin such away that the major portion towards one edge is free to expandin any direction throughout its thickness, and

" means for securingtheresilient plate to the type. bar segment adjacentits'oppositeedge,

as hereafterinore particularly explained by the following specification.I I

,Fig. 1. is a perspective view of a'type bar segment showing my deviceandthe prefer able means for se'curing'iny devicetothe segment plate.

Fig. 2 is a" sectional view through the.

lowerIpo r ti o n the segment plate showing a portion of key bar'coactlng'therew th. I a Fig; is an enlarged detail showing the meansfor securing the resilient plate to its ppo t I Figs,- 4:- to 511 showseveral alternative means of permitting 'the' free expansion of theresilientstop plate towards the printing point, and also'alternativemeansfor securing'the resili'ent' stop-plate t0 the segment plate" Inthe drawingsjlike characters of reference indicate correspondlng 'partsn "eachfigure. I I I I I I Referring to Figs. 1,2 and 3, 1includes'asegmentplate of ord nary construct on and provided'with aslotted "portion 2*ii1 iih'ibhf" I I "between the surface ofthefsegment'plate thek'ey bars Bare pivotally mounted in the usual way,as indicated in Fig 212', and a metal stop ring forming with the portion2 intervening II are :shaped recess or gro'ove -I r I.

" Application med may as,

1924 Serial nof 'iiaozer 61 is a strip ofrubber or other"resilientmaterial which is placed within'the groove;

or recess The resilient plate6 isof less 6 to permit of the freeexpansion and contraction of such edgeportion towards and awayfrom thestop ring 4 when subjected to" the blow of the typewriter key bar! "The.

printing point is secured byf suitable'ineans to the segment plate,leaving the unattached; edge free to move towards' the; printing pointas aforesaid. I v I There are'of course many'ways by which I theresilient'platemay'be secured as above set forth to the segment plate. II

I will first, however, describe the prefer: able means for accomplishingthis result.

7 are perforations formed in the plate -6 1 adjacent that edgeremotefrom the printing point and set in spaced apart positions pref:

erably four in number, as indicated Fig.

' 1 of the drawing.

v8 are screws whlch passlthrough the ori fices' threaded; orifices 9formed in that portion ofthe segment plate '1 forming the base of andare s'crewediritdinternally I the groove or rec'ess'5." The screws 8 are"provided with flat heads 10, the diametric slot 11 of which extendsentirely through the head to'the root 'of the screw shank,

thereby forming two notched openings at? each side of the shank intowhich the re silient material forming the plate 6 is forced as the headis drawn into theface ofithe plate to compress it. I Theresilientmaterial forced into the ends of the diametric groove '11 formsalocking,

"protuberance 6 engaging within thegroove so as to prevent the turningof the [screw and thereby ensure ?P rmanen securing '95 means-1301' theP -Q'Ihe Stop ring t also I has the function of protecting the upper orfreeedgeportion of the plate 6 from dust or dirt falling downward'soasto gather in,"

In Fig. 41 ha ve shown analternative com struction similar in form tothat shown in Figs. 1 to 3, with the exception that 111 this form thestop ring l is dispensed with an are shaped band 12'provide'd for thepurpose of forming a shield to shedthe dust and dirt outward so that itcannot pass into the crevice between the segment plate 1 and resi l-*ient plate 6.

In Fig. 5 I have shown a plate 13 formed of resilient material, the baseof which is flared outward as indicated at 14 and 15 and inserted inzitcorrespondingly formed groove 16. In order to permit,-in-thisconstruction, of the free exp'ansionot thefresilient-mate rial towardsthe printing point, I form a re cess or gr0ove 17 adjacent the edge 14.

In Fig. 6 I have shown a resilientstop plate similar in construction tothat shown in Fig. 5, but instead of the groove; 17 I form a. completeorifice l8extending. parallel to that edge of theresilientplate-adjacent to the printing point. 7 Y

In the construction shown in Figsr5. and,

6, that portion of the plate extending between the sides of the groovelfi projects outward therefrom to iorm the-surface with whioh the key'barcontactswhen operating.

In Fig. 7 I have-shown a structure similar to Figs. 5 and -6 butinthisfigure the edge portion of theresilient strip adjacent to the printingpoint-is honeycombed, a-s;1n-

dicated at 19,- so as-to imparttherequired expansive quality to thematerial when struck by the key bar.

In Fig. 8'I have shown a further alternative structure similar; to Figs.5, '6 and 7,

but in this figure, in orderto-provi'de the required expansive qualityto the rubber, .I convex the inner-face oftheresilient plate,

as indicatedzat 20. 1

In Fig. 9 I show a resilient plate-having lateralextensions 21 and22'at-its base1fit--- ting. freely withina dovetailed groove 23,-. theedges otthe portions 21 and 22 alone contacting with the inclinedsnrtacesi'o't the f groove 23, the outwardly projecting portion 24 ofthe resilient -plate being' clear ofthe adjacent edges of thegrooveiand-thereby forming clearance spaces '25 and 26 at each side ofthe plate, permitting free expansion of the plate when struckby the keybar.

In Fig. 10. I show a similar construction to Fig. 5, with the exceptionthat the edge'portion of the key bar contact face towards the printingpointis cut away, as indicated at 27, so as to prevent:the bulging overof the resilient material. overthe holding edge or" the retaining groovein which the resilient plate is held, andthereby prevent the cuttingofthe material which would be liable to take place ifthe plate were not somade.

In 11 I' have shown a solid resilient plate 28 having a flaring ordovetailed base 29 fitting in the correspondingly formed groove 30, thebase of which is provided the confining boundary formed by I116: wallswith a groove recess 31 beneath the edge portion of the plate 28adjacent to the printing point and into which the resilient mai terialisada aaaq expand:when struck.

Most modern typewriters have anvilor'stop' ringint'erposed' in the pathof the type bar travel to the printingsurtace, so as to overcomeblurring and ensure sharp printing. "This method is objectionable, be-

cause of the noise created by impact of the type bar against the metalanvil. lVear is also caused because ofthe-violent. sudden ob structionof the type bars, Replacing otthe hard anvil by, the substitution of aresilient;.:'

elastic anvil "plate has been suggested, but.

such means havenever been; put JintO actual practice,' because theresults .were unsatisrtacsj, tory, dueto, the peculiar choking action-,

which caused an uneven touch and irregular,

- density in the printing, this. choking action being'produced by thebase portion of the;

TG$1llGI1tplate beingJclosely confined in 21;.-

containing groove-so that-the expansion movement in the resilient.material :is-

stopped,- dampened or choked after b in -1 struck by the key bar, fromtravel-ingl throughthe confined portion .o-f-th'e plate,-

such portion being held from expansion by:?;

The constructionabove described provides:

means -for eliminatinv the objectionable compression :wave which; isincreasinglyformed as thetypeibar contactincreases',and w theobjectionable. effect va-ries with the type .110 bar -speed, and'isdifferent withethe adjacentn silient materialat more distant points. i i

bars and ones that impact ,against the-11e-- The method hitherto usedfor'holdingthe resilient plate tightly in a containing or ll I)holding-member which: vconfined it. andgripped its edges or. otherwiserestricted the-Q expansion or extension, caused the above-1 undesirableeffects. The most common method proposed was to firmly embed theresilient plate or strip in a recess or cavity-,3

formed in a type 'barsegment. Such means have never withstood thedemandsof actualw use,;for the reasons above stated."

I It has beenqfound' that the edges finuithe direction of the width ofthe resilient plate should be left free, or that at least oneedgeg; &

should beleft tree, preferably the edge near 2%;

est the printing point, as indioated in;

2 and 3 inclusiye. If theedges or portion of the edges must be confined,it is necessary that the resilient strip must have a hollow space in itssubstance, as indicated in Figs. 5 and G, or a layer of honeycombedorless dense material in its substance near the edge that receives themost pressure, vhicn'is the edge towards which the compression wavetravels, as indicated in Fig. 7, or thata space or recess be left in thematerial in the underside, preferably as near as possible to the edgethat is closest to the printing point, as indicated in Fig. 8, or thatclearance spaces be left so that a recessed or depressed portion be.formed in the segment plate supporting the resilient plate locatedadjacent one edge of such resilient plate, as indicated in Fig. 11,inorder to bring about the result desired, that is the free expansion ofthe resilient material when struck by the typewriter key bar.

It may be pointed out that if a solid resilient strip three siz ztcenthsof an inch thick is confined in a recess or trough one eighth of an inchdeep, it would be seen that the surface pressure causes compression totake place at the bottom and that the compression can only be relievedby the material pressing back and swelling up to the surface on eachside of the type bar.

It will be seen that there are three factors present, the downwardconfining compacting. the surface wave in front of the advancing contactpressure and the rebound from the tightly compacted bottom material.Vfliile some of the surface material will expand over the edgeof theholder, this movement is restricted by the adjoining material thatcannot find a space to move into.

A type bar travels to and from the print-- ing surface in a smallfraction of a second, and it must be made clear that the functioning ofa resilient stop plate must occur within such time periods, or therewould be a clogging effect that most nndesira allowing space forexpansion or relief from pressure, manufacture is sin'iplified, becausean error of four or five one thousandths is unimportant, whereas whentightly confined, a difference of one thousandth of an inch in thicknessseriously affects the proper functioning. Type bars that make a directblow are also benefited, but the space for protrusion must be increasedor both edges of thewidth must be left 'free so as to get the bestresult-s. 1

It might be also pointed out that 0. device such as I have described isapplicable to various moving parts of a typewriter which would coacttherewith to function in the same way such as the type bar the key leverrest, or for cushioning the reciprocal movement of the escapement,because confining the resilient material causes deaden ing and producesan excessive reboundwhich is undesirable.

.le. By 7 ,Although -my construction of resilient plate as-abovedisclosed may-be used alone to give satisfactory results to stopvibration, prevent blurring and accelerate the return of the'type bar,it is thought best to combine it with the regular hard anvil or stop rinas indicated before in Fig. 1, leaving a space between the two andhaving the hard anvil far enough back so that it will only come intoeffect when an extra hard blow is struck, or asa means for preventingthe indenting effect of the punctuation marks.

Instead of using securing screws 11, the resilient stop plate may besecured to the segment plate by forming recesses or orifices in theplate,'such as indicated at 32, into which is forced a resilientprojection 33'extending from the base of the plate 13 so as to expand inthe orifice 32 and thus form a locking connection, holding the plate 13to the segment plate, as indicated in Fig. 5, or the most inert edgecould be gripped by a range of some kind, preferably consisting oflittle fingers gripping at several points along the most inert edge, asindicated in Fig. l; or if desired the resilient plate may be secured tothe segment plate by cementing or vulcanizing a portion or all of theunderside direct to the carrying member, or various other methods mightbe employed which. would suggest themselves to anybody skilled in thisparticular art.

From this description it will be seen that I have devised a very simpledevice which will prevent the choking or clogging efi'ect produced inthe resilient plate when struck by the type bar, which will eliminatethe necessity for extreme accuracy in construction necessary inemploying a resilient plate rigidly secured and confined in positionupon the segment plate or other supporting member, and which therebysimplifies and cheapens the manufacture and at the same time provides adevice which improves the key touch, increases the speed, eliminatestype bar impact noise, and produces very sharp and clear printing, andalso maintains the alignment of the type, owing to de creased wear.

What I claim as my invention is:

1. In a typewriter provided with type bars, a supporting member havingan unyielding type bar contact surface, and a yielding type bar contactmember secured to the supporting member which forms a hearing supporttherefor and secured only at its edge remote from the printing point topermit free expansion of the yielding member from the point of itsattachment to the supporting member towards the, printing point whensubjected to the type bar blow.

2. A type bararrester comprising a support, and a resilientlycompressible member carried by the'support and secured thereto along theedge remote from the printing point of; the type bar and having aca'vityadjacent to itshppos-itehr free 'edge te felieve the density produced inthe "compress ible member by thetype bar blow inheritof the type bar asthe area of Contact between the, type bar and compressible memberadvances transversely thereof.

'13,. In a typewriter proyided with "typethet'y H 5 CQATSWORTI IREDDI OK.

bars, -asupporting device forming: a recess 211161 win flnyielchngtypebai ebfitaet Sfirfaheflp

